1. Field of the Invention
The present invention is related to a chamfer cutter, and more particular to a chamfer cutting tool which is used for chamfering a threaded hole.
2. Description of Related Art
In general, a countersink has to be machined in a threaded hole of a work piece, so that a head of a screw may be flush with a surface of the work piece, etc. A conventional chamfer cutter, as shown in FIGS. 7 and 8, is composed of a tool rest (40), a housing (50), a tool blade (41), an adjusting nut (60), and a locking nut (61).
The tool rest (40) has a lower smooth part (401) and an upper threaded part (402). A shaft (403) is provided on a top of the tool rest (40) for fitting in a clamping chuck (not shown or numbered). A first channel (404) is longitudinally defined through an outer periphery of the tool rest (40). Two first threaded apertures (405) are transversally defined in the outer periphery of the tool rest (40) and in communication with the first channel (404). The tool blade (41) is received in the first channel (404) and two first screws (42) respectively extend through the first threaded apertures (405) to fasten the tool blade (41). A blind hole (406) is defined at a bottom surface of the tool rest (40) and a resilient member (43) is provided in the blind hole (406).
The housing (50) has a tapering part (51) formed at a bottom end thereof. A chamber (52) is defined at a top of the housing (50). A second channel (53) is longitudinally defined at an outer periphery of the housing (50) and in alignment with the first channel (404). The tool blade (41) is also received in the second channel (53). An annular slot (54) is defined at an upper portion of the outer periphery of the housing (50).
The tool rest (40) is received in the chamber (52) with the threaded part (404) extending out from the housing (50). The adjusting nut (60) with a female thread (602) and the locking nut (61) are in turn engaged with the threaded part (404). The adjusting nut (60) has a flange (601) in alignment with the annular slot (54), and two second threaded apertures (not numbered) transversally defined through the flange (601). Two second screws (603) respectively extend through the second threaded apertures to enter into the annular slot (54) and abut an upper edge of the annular slot (54) under a force of the resilient member (43).
In machining of a threaded hole of a component, when the tapering part (51) is stopped by a periphery defining the threaded hole, the tool rest (40) can continue to move down to chamfer the threaded hole and will not stop until the second screws (603) arrive at a bottom edge of the annular slot (54).
Referring to FIG. 9, in adjustment, the locking nut (61) and the adjusting nut (60) are screwed up to decrease a distance between a cutting edge (411) of the tool blade (41) and a bottom edge of the tapering part (51). Thus, the cutter can chamfer a deeper countersink.
However, the conventional chamfer cutter has following shortcomings:
1. It is inconvenient to adjust the cutting edge (411) by screwing the adjusting nut (60) and the locking nut (61).
2. Because the threaded part is provided on the tool rest for engaging with the nuts (60, 61), the chamfer cutter is long and vibrations and shudders can transmit along the cutter during a machining operation.
3. The chamfer cutter has a high manufacturing cost because of the large number of elements.
Therefore, the invention provides an improved chamfer cutter to mitigate and/or obviate the aforementioned problems.
A main objective of the present invention is to provide a chamfer cutter which is easy to be adjusted.
Another objective of the present invention is to provide a chamfer cutter which has no vibration or shudder during use in a machining operation.
Another objective of the present invention is to provide a chamfer cutter which has a low manufacturing cost.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.